Prophylactic versus Therapeutic Administration of Intravenous Lidocaine for Suppression of Post-extubation Cough following Cataract Surgery: A Randomized Double Blind Placebo Controlled Clinical Trial

Prophylactic versus Therapeutic Administration of Intravenous Lidocaine for Suppression of Post-extubation Cough following Cataract Surgery: A Randomized Double Blind Placebo Controlled Clinical Trial

Background: Post-extubation cough causes considerable patient discomfort and in certain surgical procedures may lead to postoperative surgical complication. Different drugs and techniques have been used for the prevention of post-extubation cough with variable success rates. Prophylactic administration of lidocaine has been tried for the prevention of post-extubation cough with controversial results. No previous study has been performed to evaluate the therapeutic effect of intravenous lidocaine for treatment of post-extubation cough. This study was designed to compare the prophylactic effect of intravenous lidocaine with that of the therapeutic lidocaine in a sample of adult patients undergoing general anesthesia for cataract surgery. Methods: The study was performed in two phases. In the first phase 200 adult patients were consecutively included in the study. They were randomly divided into two groups to receive either intravenous lidocaine 1 mg/kg or the same volume of normal saline as placebo prior to extubation. Proportions of patient with post-extubation cough were compared between two groups. Patients with established cough comprised the sample of the second phase of the study in which they randomly divided into two groups to receive either intravenous lidocaine 0.5 mg/kg or placebo to abort the coughs. Proportions of patients with successful response to lidocaine were compared between two groups. Results : Proportions of patients with post-extubation cough were not significantly different in two prophylactic groups as revealed by 19 (20.7%) in lidocaine vs. 27 (28.7%) in placebo. The efficacy of prophylactic lidocaine for suppression of post-extubation cough was estimated to be 28.1%. Proportion of patients who were successfully treated in the second phase of the study was significantly higher in therapeutic lidocaine group 20 (80%) w。10 (38.5%) in placebo group (P= 0.003). Conclusions: The outcome of this study shows that prophylactic administration of lidocaine prior to tracheal extubation may be ineffective to prevent post-extubation cough. Based on the results of this study it can be recom-mended that post-extubation cough should be treated upon occurrence instead of routine prophylactic administration of lidocaine.